The present invention relates broadly to methods and apparatus or manipulating yarn end in a bobbin winding machine and, more particularly, to a method and apparatus for moving individual yarn ends into a yarn receiving disposition at a yarn end joining device in a winding station of a bobbin winding machine in the absence of proper yarn travel from a delivery bobbin to a take up bobbin. Specifically, a yarn end from the delivery bobbin is first placed in the yarn end joining device as a downstream yarn and a yarn end of the take-up bobbin is then placed in the yarn end joining device as an upstream yarn, and the yarn ends are subsequently joined together by the yarn end joining device.
Currently, at the winding stations of bobbin winders, if a yarn break occurs or if a delivery bobbin or take-up bobbin is changed, a yarn end from the incoming bobbin is spliced automatically with the yarn end from the remaining bobbin. To that end, the yarn end on the delivery bobbin and the yarn end on the take-up bobbin are automatically grasped and placed in a yarn end joining device, where the two yarn ends are either knotted together or spliced.
The tasks of searching for the yarn ends, placing them in the yarn end joining device and joining the yarn ends are done either by a movable device that moves from one winding station to another or by auxiliary devices that are permanently installed at the winding stations.
Yarn manipulating suction tubes are one known auxiliary device for placing the yarn ends in the yarn end joining device. U.S. Pat. No. 4,263,775 to Mima discloses grasping yarn coming from the delivery bobbin and placing it in the yarn end joining device by means of a pivotable suction tube that is connected directly to a negative pressure source. Another suction nozzle, which is also connected to a negative pressure source, seeks the yarn end that has run up onto the take-up bobbin, engages it, and moves it to the yarn end joining device for joining the two yarn ends. According to Mima, a separate suction tube is provided for each yarn end. Movement of the suction tubes is coordinated so that the placement of the yarn ends in the yarn end joining device will occur in proper sequence. This type of device requires a commensurate amount of space at the winding station as well as suitable controls for coordinating the movement of the two suction tubes.